This invention relates to abrasive compacts. Abrasive compacts are known in the art and consist of a mass of ultrahard abrasive particles bonded into a polycrystalline mass. The ultrahard abrasive particles currently known are diamond and cubic boron nitride. The abrasive particle content of abrasive compacts is greater than 70 percent by volume.
Abrasive compacts may be provided with a second or bonding phase or without such a phase. The second phase will generally contain a catalyst or solvent useful in the synthesis of the particular abrasive particle used in the compact. Examples of suitable catalysts or solvents for diamond synthesis are cobalt, iron and nickel. Examples of suitable catalysts or solvents for cubic boron nitride synthesis are aluminium or alloys containing aluminium.
One method of producing an abrasive compact with only a small amount of second phase is to produce a compact with such a phase and then remove substantially all that phase, e.g. by leaching. This method of producing abrasive compacts substantially free of a second phase suffers from the disadvantages that the removal step is very time consuming and does not always achieve a suitable reduction in the amount of second phase.
U.S. Pat. No. 4,224,380 discloses a temperature resistant abrasive compact and a method of making it including the steps of making an abrasive compact containing a second (metallic) phase and removing substantially all said second phase, as by leaching, e.g. acid leaching, electrolytic depletion, or liquid zinc extraction, so that the abrasive compact comprises between 0.05 and 3% by volume of said metallic phase.